<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>
<body>
    <div>111</div>
    <div class="two">222</div>
    <div>333</div>
    <script src="jquery.min.js"></script>
    <script>
        console.log($("div"));
        console.log($("div").length);

        $("div").each((index,item)=>{
            console.log(item);//DOM对象
            item.style.backgroundColor="blue";
            $(item).css("color","red");
        })

        console.log($("div").eq(0));//获取第一个 div---jq对象
        console.log($("div").get(0));//获取第一个 div---DOM对象

       //获取索引下标
        console.log($("div.two").index());//1
    </script>
</body>
</html>